docs: def download(input, filename, format='sdf', overwrite=False, resolvers=None, **kwargs):
      """ Resolve and download structure as a file """
      kwargs['format'] = format
      if resolvers:
          kwargs['resolver'] = ",".join(resolvers)
      url = API_BASE+'/%s/file?%s' % (urlquote(input), urlencode(kwargs))
      try:
          servefile = urlopen(url)
          if not overwrite and os.path.isfile(filename):
              raise IOError("%s already exists. Use 'overwrite=True' to overwrite it." % filename)
          file = open(filename, "w")
          file.write(servefile.read())
          file.close()
      except urllib.error.HTTPError:
          # TODO: Proper handling of 404, for now just does nothing
          pass